The present invention relates to a plug-in connection device for the self-actuating, for example a multipolar, electric connection of a motor vehicle trailer, in particular a semitrailer, to a towing vehicle, in particular a semitrailer tractor, with a socket and a plug, which can be disposed on the motor vehicle trailer (for example the plug) or the towing vehicle (for example the socket), during the coupling of the motor vehicle trailer to the towing vehicle can be aligned with one another and, by means of a drive, developed for example as a piston-cylinder configuration, can be moved under guidance relative to one another between an advanced connection position and a retracted resting position, where preferably a cover of the socket, by shifting the contact insert received in it and bearing the contact sleeves in the direction of the connection position can be opened self-actuatingly with the aid of the drive and, by retracting the contact insert into the resting position, can be closed again.
In such a plug-in connection device, which has already been proposed, the coupling position is to be ensured by a sensory device. Due to the large tolerances customary in motor vehicle construction, and due to the danger of contamination of the sensors during a driving operation, the precise alignment of the plug with respect to the socket, however, is difficult. Self-actuation of the connection process is therefore questionable.